This application claims the priority of German application 197 26 215.5, filed Jun. 20, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to an arrangement for manufacturing a paper can from blanks of packing material, comprising processing stations which are arranged one behind the other along a first star wheel and a second star wheel. The stations are rotatable in a cyclical motion and comprise holding devices for the blanks which can be fed to the processing stations one after the other to be put together and formed one by one. Material supply stations hold ready packing material to be processed, and feeding devices feed the packing material to each star wheel.
Paper cans, manufactured by known arrangements, consist in their finished state of a tube, on both open front sides of which a front wall is arranged. Paper cans of this type are filled after their completion, that is after the second front wall has been applied. They have for this purpose on one front wall a filling opening, which can be sealed after filling. The filling opening may also be used by the consumer as an emptying opening.
Paper cans of this type are put together using a plurality of blanks, usually three, which are at first in the form of sheets. During manufacture, these sheet-like blanks are formed into the tube or the front walls and put together as a paper can. The forming and putting together of the blanks occurs in stages in consecutive processing stations. To make a paper can, a blank is transported from processing station to processing station, whereby in subsequent processing stations further blanks required for the paper can are fed thereto. The blanks are formed and joined together in the processing stations, whereby as a rule, in each subsequent processing station a further production stage is reached.
The paper used as packing material is such that it can be provided with one or more layers of plastic. Different packing material may be used for the various blanks of a paper can. Therefore, it is conventional that the packing material for the different blanks of a paper can are each fed separately. The feed material comes in large units, for example in the form of rolled up tapes of material or stacks of blanks. In the case of material tapes, blanks in the desired form are punched out of them. In arrangements for manufacturing a paper can, the packing material is usually kept on hand in material supply stations.
One such arrangement is described in U.S. Pat. No. 5,135,462 in which two separate arrangements are joined together. Each separate arrangement is arranged to its own machine frame and comprises a star wheel with processing stations arranged thereto. The star wheels are each fed packing material from separate material supply stores. Both machine frames are connected together by a transport device. Partly completed paper cans are transported in a random stream by this transport device from the first separate arrangement to the second separate arrangement. There the paper cans are separated and processed to complete cans.
British Patent No. 704 608 discloses a further arrangement for manufacturing paper cans. This arrangement comprises a plurality of consecutively arranged processing stations, at which the paper cans are put together in stages. The processing stations are distributed over a plurality of machine frames which are connected together by transport devices. The packing material is fed from separate material supply stores. The arrangement takes up a large amount of floor space and has a very complicated design.
U.S. Pat. No. 4,490,130 discloses a machine for manufacturing paper cups which are produced from a blank for a sleeve and a blank for a bottom. The blanks for the sleeve are fed to a first star wheel and the blanks for the bottom are fed to a second star wheel. Two separate material supply stores are provided for the packing material, which stores are arranged far away from each other. As the paper cup has a relatively simple form and comprises of only two pieces, the forming and the putting together takes place only in the area of the second star wheel. It is thus possible to arrange the star wheels to a joint machine frame.
An object of the present invention is to simplify the arrangement for manufacturing paper cans.
This object has been achieved in accordance with the present invention by providing that the two star wheels and the respective work stations are arranged on a joint machine frame, to which a joint material supply station for packing material comprising various blanks is arranged.
The simplified configuration obtained the present invention results in a series of advantages.
The arrangement of the star wheels according to the present invention does away with the need for complicated transport devices, as well as alignment at the end of the transporting device, which was necessary up to now. Partly completed paper containers can be transported from the first star wheel to the second star wheel in a simple way. The transporting device between the two star wheels can be of a corresponding configuration. In addition, floor space is reduced, as only one machine frame is necessary. Both the star wheels can be driven by a joint drive in a simple design. A joint drive can also be used for most of the parts of the processing stations.
The joint material supply station for different types of packing material leads to the substantial advantage that the material feed is simplified overall. A good basis for automation of the material is thereby achieved. Even without automation, the operational stages necessary for the material supply and the material feed are considerably reduced.
The present invention makes manufacture of a complete paper can in a compact installation possible, which paper can is made up of a plurality of blanks and has no inner open paper cut edges. The paper can comprises a filling opening which can be closed by an appropriate closing element. Covering strips, stoppers or such similar elements can be used as closing elements. The closing element can be applied before filling, namely in such a way that the filling opening is not yet covered before filling, or that it can be opened again without destroying the closing element.
The filling opening and the closing element can be so configured that the filling opening can also be used as an emptying opening. In this case, it is practical when the closing element is affixed in such a way that the emptying opening still looks presentable after the consumer has removed the closing element.
The present invention also contemplates configuration of the paper can so that the consumer can create the emptying opening, for example, along a weakened line. Another contemplated approach is to provide an emptying opening in the paper can in addition to the filling opening. The emptying opening is closed by a closing element. The filling opening is then not used as an emptying opening.
The packing material for the blanks, from which the paper can is put together, is centrally fed in the installation. Of course, the packing material can fed separately for all the various blanks or other elements necessary for the manufacture of the paper can and process in the installation. The packing material can also be fed in such a way that blanks, or other elements of the paper can which belong together, are already connected. For example, for the blanks which later form the walls of the paper can, packing material can be fed which already is provided with a protected edge or with a closing element.
In one advantageous embodiment of the present invention, a plurality of holders for holding each one roll of packing material are provided at the joint material supply station. It is hereby practical when reserve rolls are arranged to the holders, thereby making advantageous when a connecting device for adhering the end of one roll with the start of a reserve roll is arranged to the material supply station. A connecting device of this type can be so configured that it can be applied to rolls of varying widths. The above mentioned measures result in a simplified construction and in particular in a reduction of operational stages.
Another advantage of the present invention arises when the material supply station comprises one holder for a roll of packing material for a sleeve, one holder for a roll of packing material for a bottom and one holder for a roll of packing material for a lid of a paper can to be manufactured.
In an advantageous embodiment the material supply station comprises a holder for a roll of packing material for a pull tab, which functions as a closing element for a filling opening of the paper can to be manufactured. The paper can, with all its component pieces, is manufacturable in a single arrangement. As already mentioned above, the pull tab can be applied in such a away that the filling opening is not yet covered. The pull tab then needs only to be sealed in a filling machine which may be arranged downstream of the installation. As already mentioned above, the pull tab can instead be already provided in the fed packing material for the walls of the paper can.
In a corresponding way, a roll of packing material for a pull tab can be fed, which serves as a closing element for an emptying opening. This pull tab can be applied by the arrangement of the present invention so that it seals closed the emptying opening. As already mentioned above, the pull tab can be already provided in the fed packing material for the wall of the paper can.
In an advantageous embodiment of the present invention, two star wheels are arranged in relation to the joint machine frame that they are disposed adjacent one another and their rotational axles extend horizontally. The configuration can thereby be further simplified and allows both the star wheels and the respective processing stations being easily accessible from one side, for example for the purpose of changing tools or for maintenance work. The drive and gear elements can be taken up in the area of the back side and are also easily accessible.
In the present invention, a transport device is provided, by way of which a partly completed paper can is transportable in a linear movement from the first star wheel to the second star wheel. The star wheels are advantageously arranged such that in the area of the transport device a mounting device of the first star wheel is disposed opposite a mounting device of the second star wheel. Thereby, the transfer of a partly completed paper can from the first star wheel to the second star wheel can be effected in a simple way.
A processing station for forming a sleeve, a processing station for applying a lid comprising a filling opening and a processing station for localized partial fixing of a pull tab on the packing material for the lid are arranged to the first star wheel, in accordance with the present invention, whereas a processing station for applying a bottom is arranged to the second star wheel. Thereby, a paper can comprising a pull tab is manufacturable in a simple way. As the pull tab is only partially locally fixed, the filling opening can be easily uncovered by removing the pull tab.
Another advantage of the present invention arises when a processing station for removing the pull tab from the filling opening is arranged to the first star wheel. The processing station is arranged downstream of the processing station for localized partial fixing of the pull tab. The partly completed paper can is thus be transferable to the second star wheel with an uncovered filling opening. A machine tool is insertable into the filling opening in order to facilitate the application of the bottom.